High-power pulsed magnetron sputtering process as well as a high-power electrical energy source

Abstract

A high-power pulsed magnetron sputtering process, wherein within a process chamber by means of an electrical energy source a sequence of complex discharge pulses is produced by applying an electrical voltage between an anode and a cathode in order to ionize a sputtering gas. The complex discharge pulse is applied for a complex pulse time. The cathode has a target comprising a material to be sputtered for the coating of a substrate, and the complex discharge pulse includes an electrical high-power sputtering pulse having a negative polarity with respect to the anode and being applied for a first pulse-time, the high-power sputtering pulse being followed by an electrical low-power charge cleaning pulse having a positive polarity with respect to the anode and being applied for a second pulse-time. The ratio τ 1 /τ 2 of the first pulse-time (τ 1 ) in proportion to the second pulse-time (τ 2 ) is 0.5 at the most.

The invention claimed is: 
     
       1. A high-power pulsed magnetron sputtering process, wherein:
 producing within a process chamber via an electrical energy source, a sequence of complex discharge pulses to apply an electrical voltage (V) between an anode and a cathode in order to ionize a sputtering gas; and 
 coating a substrate with a ceramic material, 
 wherein each complex discharge pulse is applied for a complex pulse time (τ) and the cathode being a target comprising a material to be sputtered for the coating of the substrate; 
 wherein the complex discharge pulse comprises an electrical high-power sputtering pulse having a negative polarity with respect to the anode that is applied for a first pulse-time (τ 1 ) followed by an electrical low-power charge cleaning pulse having a positive polarity with respect to the anode that is applied throughout an entire second pulse-time (τ 2 ), 
 wherein a voltage of the high-power sputtering pulse is between 400V and 2000V, 
 wherein a peak power density of the high-power sputtering pulse is between 1 and 20 KW/cm 2 , 
 wherein a ratio τ 1 /τ 2  of the first pulse-time (τ 1 ) in proportion to the second pulse-time (τ 2 ) is 0.5 at the most, and 
 wherein subsequent to the low-power charge cleaning pulse and before another high-power sputtering pulse is applied, the process further comprises at least one of switching off and setting to zero the voltage (V) applied between the anode and the cathode for a third pulse-time (τ 3 ), said third pulse-time (τ 3 ) being less than the second pulse-time (τ 2 ), and 
 wherein at least one of: 
 a peak current density of the high-power sputtering pulse is between 0.05 A/cm 2  and 5 A/cm 2 , and 
 a peak power of the high-power sputtering pulse is between 0.1 MW and 3 MW. 
 
     
     
       2. A process in accordance with  claim 1 , wherein the ratio τ 1 /τ 2  of the first pulse-time (τ 1 ) in proportion to the second pulse-time (τ 2 ) is between 0.005 and 0.5. 
     
     
       3. A process in accordance with  claim 1 , wherein at least one of the high-power sputtering pulse and the low-power charge cleaning pulse is at least one of a low frequency AC-voltage, a rectified low frequency AC-voltage, and a DC-voltage pulse. 
     
     
       4. A process in accordance with  claim 3 , wherein the frequency of the at least one of the high-power sputtering pulse and the low-power charge cleaning pulse is between 0 Hz and 10 kHz. 
     
     
       5. A process in accordance with  claim 1 , wherein at least one of:
 the voltage of the high-power sputtering pulse is between 600V and 2000V, and 
 a voltage of the low-power charge cleaning pulse is between 0V and 500V. 
 
     
     
       6. A process in accordance with  claim 1 , wherein the first pulse-time (τ 1 ) of the high-power sputtering pulse is between 1 μs and 5000 μs. 
     
     
       7. A process in accordance with  claim 1 , wherein at least one of:
 the second pulse-time (τ 2 ) of the low-power charge cleaning pulse is longer than 25 μs, and 
 the complex pulse time (τ) is between 50 μs and 1000 ms. 
 
     
     
       8. A process in accordance with  claim 1 , wherein an ionization degree of the sputtering gas is between 3% and 100%. 
     
     
       9. A process in accordance with  claim 1 , wherein at least one of:
 the sputtering method for coating the substrate is a reactive sputtering method or a non-reactive sputtering process. 
 
     
     
       10. High-power electrical energy source for producing a complex discharge pulse for carrying out a process in accordance with  claim 1 . 
     
     
       11. A process in accordance with  claim 9 , wherein the ceramic material comprises at least one of a nitride, an oxide and a carbide. 
     
     
       12. A high-power pulsed magnetron sputtering process, said process comprising:
 producing within a process chamber via an electrical energy source, a sequence of complex discharge pulses to apply an electrical voltage (V) between an anode and a cathode in order to ionize a sputtering gas, said cathode comprising an oxide target material that is sputtered onto a substrate: 
 applying each complex discharge pulse for a complex pulse time (τ), said complex discharge pulse comprising an electrical high-power sputtering pulse having a negative polarity with respect to the anode that is applied for a first pulse-time (τ 1 ) followed by an electrical low-power charge cleaning pulse having a positive polarity with respect to the anode that is applied for a second pulse-time (τ 2 ) that is longer than the first pulse time (τ 1 ); 
 subsequent to the electrical low-power charge cleaning pulse and before another electrical high-power sputtering pulse is applied, switching off and/or setting to zero the electrical voltage (V) applied between the anode and the cathode for a third pulse-time (τ 3 ), said third pulse-time (τ 3 ) being less than the second pulse-time (τ 2 ): 
 utilizing a voltage of the high-power sputtering pulse of between 600V and 2000V; and 
 utilizing a peak power density of the high-power sputtering pulse of between 1 and 20 KW/cm 2 , 
 wherein a ratio τ 1 /τ 2  of the first pulse time (τ 1 ) in proportion to the second pulse-time (τ 2 ) is 0.5 at most, and 
 wherein at least one of: 
 a peak current density of the high-power sputtering pulse is between 0.05 A/cm 2  and 5 A/cm, and 
 a peak power of the high-power sputtering pulse is between 0.1 MW and 3 MW. 
 
     
     
       13. A high-power pulsed magnetron sputtering process, said process comprising:
 producing within a process chamber via an electrical energy source, a sequence of complex discharge pulses to apply an electrical voltage (V) between an anode and a cathode in order to ionize a sputtering gas, wherein said cathode is a target comprising a material to be sputtered for coating on a substrate; 
 applying each complex discharge pulse for a complex pulse time (τ), said complex discharge pulse comprising an electrical high-power sputtering pulse having a negative polarity with respect to the anode that is applied for a first pulse-time (τ 1 ) followed by an electrical low-power charge cleaning pulse having a positive polarity with respect to the anode that is applied for a second pulse-time (τ 2 ); 
 subsequent to the electrical low-power charge cleaning pulse and before another electrical high-power sputtering pulse is applied, switching off and/or setting to zero the electrical voltage (V) applied between the anode and the cathode for a third pulse-time (τ 3 ), said third pulse-time (τ 3 ) being greater than the first pulse-time (τ 1 ) and less than the second pulse-time (τ 2 ); 
 utilizing a peak voltage of the high-power sputtering pulse of between 800V and 2000V; 
 utilizing a peak power density of the high-power sputtering pulse of between 1 and 20 KW/cm 2 ; and 
 the coating on the substrate being a ceramic material, 
 wherein a ratio τ 1 /τ 2  of the first pulse-time (τ 1 ) in proportion to the second pulse-time (τ 2 ) is 0.5 at most, and 
 wherein at least one of: 
 a peak current density of the high-power sputtering pulse is between 0.05 A/cm 2  and 5 A/cm 2 , and 
 a peak power of the high-power sputtering pulse is between 0.1 MW and 3 MW. 
 
     
     
       14. A process in accordance with  claim 13 , wherein during the third pulse-time (τ 3 ) time is provided in order to relax into a starting state. 
     
     
       15. A process in accordance with  claim 1 , wherein during the third pulse-time (τ 3 ) time is provided in order to relax into a starting state. 
     
     
       16. A process in accordance with  claim 12 , wherein the third pulse-time (τ 3 ) is less than the second pulse-time (τ 2 ).